Midscreen knockdown tool primarily, along with granting combos via 2D>623[K]~4 (Blue). You'll want to get used to confirming into it and canceling into 236H for okizeme. As a footsie tool it is rather lackluster, and on block it is rather unsafe, with subpar special cancels that are also unsafe. It does serve as a competent punish for moves like Stun Dipper and Greed Sever at ranges where the only rewarding alternative would be 5S>214K with 50 meter.
Another unique quality of 2D is that it is special cancelable throughout its recovery frames, to ensure you can confirm into 236H okizeme. An avenue this quirk opens up is the ability to delay cancel 2D into 236S YRC, rather than PRC, giving you some repressure opportunities.
Make sure to practice hit confirming this move from pressure strings, otherwise you will give your opponent needless punishes/turns.